The present invention relates to a solid-state image pick-up apparatus that alternately transfers the electric charges acquired by a plurality of sensor rows to output them or that performs addition of the electric charges of pixels in the same row to output them, and also relates to a driving method therefor and an image input apparatus.
An image input apparatus that is applied to a scanner or a copier uses, a solid-state image pick-up apparatus having a linear sensor, and inputs an image, by scanning the read position of the solid-state image pick-up apparatus.
There has in recently years been a strong demand for the improvement of read resolution, and the increase of read speed. Regarding the linear sensor as well, there has hitherto been developed the one that copes with such demand by using a plurality of sensor rows. For example, in the solid-state image pick-up apparatus comprising two rows of sensors, one of the sensor rows and the other of them are arranged so as to be displaced from each other by a half pitch of the pixels. In order that, the electric charges acquired by one of the sensor rows and the electric charges acquired by the other of them may be multiplexed and alternately outputted.
Also, in case of outputting a signal obtained by adding the electric charges of pixels, the timing of a reset pulse signal for causing discharge of the electric charges of a floating diffusion amplifier that is electric-charge/voltage conversion means is controlled so that, the electric charges acquired from the pixels by both of the sensor rows and alternately transferred to the floating diffusion amplifier may be added there to each other and outputted therefrom.
However, when the addition of the electric charges is performed by the floating diffusion amplifier in the multiplexing structure type of solid-state image pick-up apparatus as described above, after the electric charges acquired by one of the sensor rows have been transferred to the floating diffusion amplifier, the electric charges acquired by the other thereof are transferred to be added there. Therefore, it is impossible to obtain the added output until the electric charges acquired by the other of the sensor rows has been transferred to the floating diffusion amplifier, with the result that a time period for the added output is shortened. Consequently, a problem is raised that signal processing in the succeeding stage will be difficult to perform. Moreover, as compared to the case where the electric charges acquired by both of the two sensor rows are alternately outputted, a cyclic period for obtaining the added output becomes delayed or lengthened. Accordingly, another problem is raised that the technique of adding the electric charges cannot cope with the demand for speedy signal processing in the subsequent stage.
A solid-state image pick-up apparatus, a driving method therefor, and an image input apparatus according to the present invention have been developed in order to solve the above-described problems. Specifically, the solid-state image pick-up apparatus of the present invention comprises: a first charge transfer row for transferring electric charges acquired by a first light-receiving pixel row; a second charge transfer row for transferring electric charges acquired by a second light-receiving pixel row; a multiplex section for transferring the electric charges, transferred from the first charge transfer row and second charge transfer row toward an electric-charge/voltage conversion means, and signal generation means for, in case of an alternately output mode, applying signals to each other to a final stage of the first charge transfer row and a final stage of the second charge transfer row and that in the case of an add-and-output mode, applying to the final stage of the second charge transfer row a signal for accumulating the electric charges until a transfer time when the electric charges to be added to each other are transferred by the second charge transfer row comes.
In case of an add-and-output mode, the above-described present invention applies to the final stage of the second charge transfer row a signal for accumulating the electric charges until a transfer time when the electric charges to be added to each other are transferred by the second charge transfer row comes. Therefore, at a position before the final stage of the second charge transfer row there is performed accumulation, i.e. addition of the electric charges that have been transferred on by the second charge transfer row. Also, while the signal is being applied to the final stage of the second charge transfer row, the electric charges that have been transferred on by the first charge transfer row to the multiplex section are sent. Then, at an initial stage of the multiplex section, there is performed accumulation, i.e. addition of the electric charges that have been transferred by the first charge transfer row until a transfer time when the electric charges to be added to each other are transferred by the second charge transfer row comes.
The driving method for driving the solid-state image pick-up apparatus of the present invention is one for driving a solid-state image pick-up apparatus comprising: a first charge transfer row that transfers electric charges acquired by a first light-receiving pixel row; a second charge transfer row that transfers electric charges acquired by a second light-receiving pixel row; and a multiplex section that transfers the electric charges which have been transferred by the first charge transfer row and second charge transfer row toward an electric-charge/voltage conversion means. The driving method includes the steps of in the case of an alternately-output mode, applying signals in opposite phase to each other to a final stage of the first charge transfer row and a final stage of the second charge transfer row, respectively, and, in case of an add-and-output mode, applying to the final stage of the second charge transfer row a signal for accumulating the electric charges until a transfer time when the electric charges to be added to each other are transferred by the second charge transfer row comes.
In the above-described present invention, in the case of the add-and-output mode, there is applied to the final stage of the second charge transfer row a signal for accumulating the electric charges until a transfer time when the electric charges to be added to each other are transferred by the second charge transfer row comes. Therefore, before the final stage of the second charge transfer row there is performed accumulation, i.e. addition of the electric charges that have been transferred by the second charge transfer row. Also, while the signal is being applied to the final stage of the second charge transfer row, the electric charges that have been transferred on by the first charge transfer row are sent to the multiplex section. Then, at an initial stage of the multiplex section, there is performed accumulation, i.e. addition of the electric charges that have been transferred by the first charge transfer row until a transfer time when the electric charges to be added to each other are transferred by the second charge transfer row comes.
The image input apparatus of the present invention uses a solid-state image pick-up apparatus comprising: a first charge transfer row that transfers electric charges acquired by a first light-receiving pixel row; a second charge transfer row that transfers electric charges acquired by a second light-receiving pixel row; a multiplex section that transfers the respective electric charges which have been transferred by the first charge transfer row and second charge transfer row, toward an electric-charge/voltage conversion means; and signal generation means that, in case of an alternately-output mode, applies signals in opposite phase to each other to a final stage of the first charge transfer row and a final stage of the second charge transfer row and that, in case of an add-and-output mode, applies to the final stage of the second charge transfer row a signal for accumulating the electric charges until a transfer time when the electric charges to be added to each other are transferred by the second charge transfer row comes.
In the above-described present invention, in the case of the add-and-output mode, there is applied to the final stage of the second charge transfer row a signal for accumulating the electric charges until a transfer time when the electric charges to be added to each other are transferred by the second charge transfer row comes. Therefore, before the final stage of the second charge transfer row there is performed accumulation, i.e. addition of the electric charges that have been transferred by the second charge transfer row. Also, while the signal is being applied to the final stage of the second charge transfer row, the electric charges that have been transferred by the first charge transfer row to the multiplex section are sent. Then, at an initial stage of the multiplex section, there is performed accumulation, i.e. addition of the electric charges that have been transferred by the first charge transfer row until a transfer time when the electric charges to be added to each other are transferred by the second charge transfer row comes. As a result of this, it becomes possible to obtain an output image in which adjacent-pixel charges transferred by each of the respective charge transfer rows are added to each other.